Expression device for pneumatically-operated musical instruments.



R. A. LEADBETER. EXPRESSION DEVICE FOR PNEUMATIGALLY OPERATED MUSICAL INSTRUMENTS.

APPLICATION FILED JULY 16, 1912.

1,103,213. Patented July 14, 1914.

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"HE NORRIS PETERS C0, PHOTO-LITHO. WASHINGTON D C UNITED STATES PATENT OFFICE.

RICHARD A. LEADBETER, OF DETROIT, MICHIGAN, ASSIGNOR TO THE FARRAND COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

EXPRESSION DEVICE FOR PNEUMATICALLY-OFERATED MUSICAL INSTRUMENTS.

Specification of Letters Patent.

Patented July 14, 1914.

Application filed July 16, 13-12. Serial No. 709,687.

T 0 all whom it may concern:

Be it known that I, RICHARD A. LEAD- BETER, a citizen of the United States of America, residing at Detroit, in the county of -Wayne and State of Michigan, have invented certain new and useful Improvements in Expression Devices for Pneumati- Cally-Operated Musical Instruments, of which the following is a specification, reference being had therein to the accompanying drawings. 4

The invention relates to expression devices for pneumatically operated, self-playing musical instruments, being particularly adapted for use in connection with percussion instruments, such as pianos.

Heretofore various devices have been employed for accentuating certain notes in the music, some of which have been operated by the pumping pedal. Where however these accentuating devices are controlled solely by the pedal, they have failed to respond as quickly as isdesirable for the proper accentuation of the music.

The presentinvention is designed to overcome this objection and consists first in the means employed for instantaneously changing the pneumatic pressure upon a proper manipulation of the pedal, and further in the peculiar construction and arrangements of parts as hereinafter set forth.

In the drawings: Figure l is a cross section through the bellows and pumping pedal for a self-playing musical instrument, to which my improvement is applied. Fig. 2 is a section through the communicating port at right angles to that shown in Fig. l.

A is the storage-bellows; B the pumpingbellows; and C the actuating pedal for said pumping bellows. The storage-bellows A is provided with suitable springs (not shown) for resisting the collapsing of the same, and which determines the normal pneumatic pressure at which the instrument is operated, which pressure will gradually increase as the storage-bellows approaches a fully collapsed position. D is an inner bellows within the storage-bellows A, having its movable part D in proximity to the movable part A of the outer bellows, with a bearing member E therebetween. The arrangement is such that the outer and inner bellows will normally move together and to permit of the equalization of the pneumatic pressure within the outer and inner chambers a normally open port F is arranged to connect the same.

Heretofore constructions as thus far described, have been employed in which the port F is restricted, so that when a sudden stroke is given to the pedal the area of the port will be insufficient to equalize the pressure in the inner and outer chambers. This will cause the higher pneumatic pressure in the inner bellows to resist the collapsing of the same and of the outer bellows, the effect being the same as increasing the tension of the resisting spring, and consequently increasing the power of the playing pneumatlcs. ate, but experience has demonstrated that the accentuation is not as marked as is frequently desirable, and furthermore requires a very quick operation of the pedal to produce any effect. On the other hand if the restriction of the port F is increased the response of the accentuating device will be easier, but there is then danger of accentuating where it is not desired. W'ith my improved construotion I have avoided this difiiculty; first, by providing a port F of sufii cient area to quickly and freely equalize the pressure within the inner and outer chambers under normal conditions, and, second, by providing a valve for completely closing this port, which is actuated by a sudden stroke of the pedal and when closed will instantaneously raise the pneumatic pressure. By such a construction it is possible to accentuate an individual note in a manner that cannot be accomplished by the continuously open restricted port. It also avoids danger of accentuating where not desired, and witl out regard to the number of pneumatics that are simultaneously under operation.

In the specific construction shown, G is the valve for closing the port F, which is arranged in a suitable housing H below the bar I in which the port F is formed, the port F comprising two bores F and F both communicating with the chamber within the housing H and one bore communicating with a space within the inner bellows D, while the outer bore is in communication with the chamber in the outer bellows outside of the inner bellows. The valve G normally rests upon the bottom of the housing H and will permit the air to flow unobstructedly through the ports between the inner and outer bellows. When however a sudden impulse is Such a construction will accentugiven to the pedal the increased velocity of air passing through the ports F and the lateral port within the housing H will create a suction which will actuate the valve G, raising it to its seat and stopping further flow through the ports. As soon as the pressure is. equalized which occurs quickly by the exhausting action of the playing pneumatics, the valve G will drop from its seat, again opening the ports and permitting a free flow of air therethrough.

To render the action of the valve H more positive and to prevent danger of its adhering to its seat, a light spring J is connected thereto, through the medium of a stem K.

What I claim as my invention is:

1. An expression device for pneumatically operated self playing musical instruments including a storagebellows, a bellows within said storage-bellows collapsible therewith, means for actuating the bellows, the chambers within and without said inner bellows being normally in coimnunication, and means controlled by the bellows actuating means for cutting oif communication between said chambers.

2. An expression device for pneumatically operated musical instruments, comprising a storage-bellows, a bellows within said storage-bellows collapsible and expansible therewith and having an air passage normally establishing free communication between the spaces within the outer and inner bellows, bellows actuating means which when operated force air through said air passage, and means controlling the passage of air through said passage and acting to close the passage when air under excessive pressure is introduced in the passage.

3. An expression device for pneumatically operated musical instruments, comprising a storage-bellows, an inner bellows collapsible and expansible with said storage-bellows a bar forming a common portion of the inner and outer bellows, said bar being provided with a port to establish communication between the chambers therein, said portion having a laterally extending housing, a valve arranged in the laterally extending housing and normally open, and means for forcing air through the port to actuate the bellows, said valve being actuated when the pressure of air is suddenly increased to close said portwhereby communication between the chemhers is checked.

at. An expression device for pneumatically operated musical instruments, comprising a storage-bellows, a bellows Within said storage-bellows, collapsible and expansible therewith, a bar forming a common member of the outer and inner bellows ported for communicating respectively therewith, a recessed casing communicating with bot-h of said ports, and a valve within said casing adapted to seat to close the port communicating with the, outer bellows, but normally separated from its seat.

5. An expression device for pneumatically operated musical instruments, comprising a storage-bellows, a pneumatic resistor for increasing the tension of said storage bellows, provided with a normally open port for throwing it out of action, a pump for exhausting said storage-bellows, and a valve responding to a sudden impulse of said pump for closing said port, and throwing said pneumatic resistor into action.

In testimony whereof I atlix my signature in presence of two witnesses.

RICHARD A. LEADBETER.

Witnesses JAMES P. BARRY, DELBERT COLLINS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

